While subspecies taxonomy of Elephas maximus has varied among authors, the most recent treatment (Shoshani and Eisenberg 1982) recognizes three subspecies: E. m. indicus on the Asian mainland, E. m. maximus on Sri Lanka, and E. m. sumatranus on the Indonesian island of Sumatra. Borneo's Elephants have traditionally been included in E. m. indicus (Shoshani and Eisenberg 1982) or E. m. sumatranus (Medway 1977, but see Fernando et al. 2003 and Cranbrook et al. 2008 for discussion of whether the elephants of Borneo are indigenous to the island). These subspecies designations were based primarily on body size and minor differences in coloration, plus the fact that E. m. sumatranus has relatively larger ears and an extra pair of ribs (Shoshani and Eisenberg 1982). The Sri Lankan subspecies designation is only weakly supported by analysis of allozyme loci (Nozawa and Shotake 1990), but not by analysis of mitochondrial DNA (mtDNA) sequences (Hartl et al. 1996, Fernando et al. 2000, Fleischer et al. 2001). However, current patterns of mtDNA variation suggest that the Sumatran subspecies is monophyletic (Fleischer et al. 2001), and consequently this taxon could be defined as an evolutionarily significant unit (ESU). This suggests that Sumatran Elephants should be managed separately from other Asian elephants in captivity, and is also an argument for according particularly high priority to the conservation of Sumatran Elephants in the wild.

Justification:
The Sumatran Elephant (E. m. sumatranus) meets criterion A2c for Critically Endangered (CR). Taking ca. 25 years as a single generation (sensu IUCN 2001) for Asian Elephants, then over 69% of potential Sumatran Elephant habitat has been lost within just one generation (the last 25 years) and the driving forces that are causing the habitat loss are still continuing essentially unchecked. There is clear direct evidence from two provinces (Riau and Lampung) to show that entire elephant populations have disappeared as a result of the habitat losses of the past 25 years: nine populations have been lost since the mid-1980s in Lampung (Hedges et al. 2005) and a 2009 survey of nine forest blocks in Riau that had elephant herds in 2007 revealed that six herds had gone extinct (Desai and Samsuardi 2009). That this pattern will continue seems certain.

Note that we use the term “potential elephant habitat” when discussing the rate of elephant habitat loss since 1985. This is because some of the forested areas that have been lost since 1985 elephants did not contain elephants in 1985; however, it is entirely reasonable to infer that elephants occurred much more widely across Sumatra in the 1930s than they did in 1985 since the 1985 elephant distribution map was the first time we had an island-wide understanding of elephant distribution on the island, and it was not a complete picture even then. Thus we infer that all the forest lost since 1985 was elephant habitat in the 1930s, or – in other words – the forest lost since 1985 alone represents a loss of 69% of Sumatran Elephant habitat since the 1930s (three elephant generations). Since elephants almost certainly occurred in areas outside their 1985 distribution in the 1930s and because much of the forest and other land cover types lost have been the better quality (preferred) lowland elephant habitat, we conclude that the inferred or suspected population size reduction for Sumatran Elephants over the last three generations must have been at least 80%. This conclusion is greatly strengthened by the fact that much of the remaining forest cover is in blocks smaller than 250 km², which are too small to contain viable elephant populations: this has the effect of increasing the real impact – on elephant numbers – of habitat loss beyond the figures suggested by forest loss alone. Therefore E. m. sumatranus meets criterion A2c for Critically Endangered (CR).

Home to the Sumatran Elephant subspecies (E. m. sumatranus), Sumatra is thought to hold some of the most significant Asian Elephant populations outside of India. Yet, within the Asian Elephant’s range, Sumatra has experienced one of the most rapid deforestation rates (Uryu et al. 2010).

In mid 1980s, when about 50% of natural forest remained on the island, elephant populations persisted in 44 discrete populations on all of the island’s eight provinces (Hedges et al. 2005).

1985: An island-wide rapid survey suggested that between 2,800 and 4,800 elephants lived in the wild in 44 ranges in all eight mainland provinces of Sumatra (Blouch and Haryanto 1984). Riau Province was believed to have the largest elephant population in Sumatra.

2002: Sumatra was still thought to contain some of the largest populations of Asian elephants outside of India and Sri Lanka. Rigorous dung density based surveys in Lampung Province’s two national parks, Bukit Barisan Selatan and Way Kambas, produced population estimates of 498 (95% CI=[373, 666]) and 180 (95% CI=[144, 225]) elephants, respectively. But province-wide surveys at the same time also showed that by 2002 elephants had gone locally extinct in nine of 12 elephant ranges recorded in Lampung in the early 1980s (Hedges et. al. 2005).

2007: Guesstimates suggested that between 2,400 and 2,800 elephants live in the wild (Soehartono et al. 2007). Given the very high number of elephants brought into captivity since 1985 (Mikota et al. 2003), the high mortality experienced during these government capture-and-translocation operations, and the high numbers of elephants lost to retaliatory killing after human–elephant conflict (WWF 2008) and poaching (based on local newspaper reports), it is highly likely that Sumatra’s total elephant population size in 1985 might actually have been greater than even that year’s high estimate of 4,800 elephants suggests. In any case, in only one generation (between 1985 and 2007) Sumatra may have lost up to 50% of its elephants.

2008: By 2008, elephants had become locally extinct in 23 of the 43 ranges identified in Sumatra in 1985, indicating a very significant decline of the Sumatran elephant population up to that time. By 2008, the elephant was locally extinct in one of Sumatra’s eight mainland provinces (West Sumatra) and at risk of being lost from North Sumatra Province too. Only ca. 350 elephants survived across nine separate ranges in Riau Province, which in 1985 was considered to have the largest elephant population in Sumatra with over 1,600 individuals.

Post-2008: Simple extrapolations from past population history suggests that Riau’s last surviving elephants may soon disappear if the current trend of forest loss continues (Uryu et al. 2008). Indeed, a 2009 survey of nine forest blocks in Riau that had elephant herds in 2007 revealed that six herds had gone extinct (Desai and Samsuardi 2009).

Systematic study on the population of Sumatran Elephants is lacking from most of the elephant’s distributional range. Province-wide assessments have been conducted in Riau (Desai and Samsuardi 2009) and Lampung (Hedges et al. 2005). However, rigorous population estimates are only available from two protected areas in Lampung, namely Way Kambas National Park and Bukit Barisan Selatan National Park (Hedges et al. 2005, Soehartono et al. 2007).

Riau. Harboring extensive flat lowland forest that is a prime habitat for elephant, Riau province was one of the strongholds for elephant conservation. However, elephant numbers in this province dropped by 84% in less than 25 years (Uryu et al. 2007). The population declined from ca. 1,342 in 1984 to ca. 210 in 2007. Due to habitat fragmentation, the number of fragmented elephant populations (“pockets”) increased from nine in 1984 to 16 in 1999. By 2007, mainly due to removal and killings related to conflicts, elephants were completely extirpated in several “pockets” including Rokan Hilir, Kerumutan, Koto Panjang, Bukit Rimbang Baling, Tanjung Pauh and Bukit Suligi. Thorough population estimates are not yet available the latest assessment indicates that all but two of these fragmented elephant populations are unlikely to survive over the long term.

West Sumatra. Elephants have been completely extirpated from this province.

Lampung. Twelve of the 44 Sumatran elephant populations identified in the mid-1989s occurred in Lampung Province. But, according to surveys conducted in 2001 and 2002 only three were still extant in 2002, and one of those was not considered viable (Hedges et al. 2005). Surveys in the early 2000s using dung density based methods in Lampung Province’s two national parks, Bukit Barisan Selatan and Way Kambas, produced population estimates of 498 (95% CI=[373, 666]) and 180 (95% CI=[144, 225]) elephants, respectively (Hedges et al. 2005). New field surveys using fecal DNA based capture–recapture methods are currently underway in the two national parks (S. Hedges pers comm).

Elephants largely use lowland forests and gentle hills below an altitude of 300 m. While the elephants in Sumatra may have habitat use patterns that differ, it is generally known from long-term studies of elephants across Asia that lowland forests are a preferred habitat (Alfred el. al. 2005, Williams 2010). Forest loss in the lowlands is higher than forest loss at all altitudes and including habitats such as peat forests, where elephants are not present.

Follow the link below for further information about national loss of natural forest in Sumatra.

Due to conversions of forests into human settlement and agricultural areas, many of the Sumatran Elephant populations have come into serious conflicts with human. As the results, many wild elephants have been removed from the wild, or directly killed. In addition to killing related to conflicts, elephants are also targets of illegal killing for their ivory. Now, Sumatran Elephant lives only in seven provinces, many of which are under increased pressure of habitat loss and imminent conflicts with human.

Although as a species Sumatran Elephants are protected under Indonesia law, 85% of their habitats which are located outside of protected areas, are outside of the protection system and likely to be converted to agricultural and other purposes.